As a consequence of the transition from an intravenous supply of nutrients in the fetus to intermittent oral feeding after birth, the newborn's behavior begins to play an important role in regulating nutrient intake by eliciting feedings from adult caregivers. The overall objective of the proposed interdisciplinary research is to discover how newborn behavioral organization is influenced by normal fuel metabolism. Two studies are proposed: The specific aims of Study 1 are: (a) To document the changes in the organization of sleep-wake states, the level of general motor activity, and the occurrence of specific behavior patterns during the hours between two feedings, and the concurrent changes in the circulating levels of the major fuels, insulin, and the catecholamines in normal newborns 2-3 days after birth. Data analysis will focus on the relationships between the behavioral and metabolic variables. (b) To determine the effects of a non- nutritive feeding on the behavioral and metabolic variables, and the coupling between them, by comparing newborns fed water vs. formula (equal volumes). Data analysis will focus on determining which aspects of newborn behavior are sensitive to the induced changes in circulating fuels, insulin, and catecholamines. The specific aims of Study 2 are to examine the behavioral metabolic coupling investigated in Study 1 under different and more extreme metabolic conditions by studying newborns in the first few hours after birth. In both studies, spontaneous movement, respiration, eye opening, and crying will be recorded to determine sleep-wake states and general motor arousal. Specific motor patterns, such as mouthing, will be identified from high resolution videotape recordings. Blood levels of glucose, free fatty acids, beta- hydroxybutyrate, acetoacetate, insulin, dopamine, norepinephrine, and epinephrine will be measured in 1 ml samples drawn at 30 min. intervals. The methods of data collection and analysis (behavioral and metabolic) have already been developed and used successfully in earlier work. The results will begin to define how fuel metabolism and behavior may be related in the newborn, and contribute to our general understanding of the role behavior plays in postnatal adaptation. Furthermore, the results will provide the empirical and technical foundation for studies of the postnatal development of behavioral-metabolic coupling and alterations in normal coupling which might contribute to early feeding problems.